compatibilizer in their blends, such as PS-graft-PB copolymer, Dow Chemical
Company has produced commercial hard-and-tough high-impact PS (HIPS),
exhibiting the advantages of both blend components. PB rubber particles are
distributed in the PS matrix, actively absorb the energy of stress concentration
upon imposing the external stress, and meanwhile generate a huge amount of crazing
surrounding the particles, inducing the effective toughening, as illustrated in Fig.6.23
(Bucknall and Smith 1965 ). Souheng Wu found that the average distance between
rubber particles needs to be smaller than a critical value to achieve thebrittle-ductile
transition(Wu 1985 ). Recently, the hierarchical complex structure containing small
plastic particles inside the discrete rubber particles via spontaneous two-step phase
separation can effectively realize such blend-toughening.
Question Sets
- Why does polymer exhibit a significant feature of viscoelasticity?
- Why could the soft rubber sheet not resist the bullet shooting?
- Why can one say that the glass transition is a dynamic relaxation transition?
- Why can some semi-crystalline polymer plastics be cold-drawn into single-axis
or double-axes oriented thin films, and the other not? - Why are most of adhesives made of polymer materials?
- How can plastics and rubbers make blends to reach a better toughening effect?
References
Adams G, Gibbs JH (1965) On the temperature dependence of cooperative relaxation properties in
glass-forming liquids. J Chem Phys 43:139–146
Angell CA (1985) Spectroscopy, simulation, and the medium range order problem in glass. J Non-
Cryst Solids 73:1–17
Angell CA, Dworkin A, Figuiere P, Fuchs A, Szwarc H (1985) Strong and fragile plastic crystals.
J de Chimie Phys, Phys-Chim Biol 82:773–779
Fig. 6.23 Illustration of rubber particles absorbing impact energy to generate a huge amount of
crazing in the matrix of high-impact polystyrene
References 123